Anyone putting their G28 and 29 commands before heating the nozzle??

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(Griffin Paquette) #1

Anyone putting their G28 and 29 commands before heating the nozzle?? I hate how my nozzle drips during leveling and was thinking that I could change the start code to level before heating.

(Justin Nesselrotte) #2

Yeah, I think on one of my printers I had it set to heat the bed, G28, G29, then heat the nozzle.

(Tom Nardi) #3

That’s how I have it setup, level and then heat. Though it still drips and I always try to wipe the nozzle before the print actually begins.

The only issue I’ve ever had is that if there was some hard plastic stuck to the nozzle from the past print, that can crash into the bed during the leveling.

(Sebastian Schmidt) #4

@Tom_Nardi ​ and that’s why nozzle heats first :wink:

But I think a better idea would be not change the order but lower the temp of nozzle.

So don’t heat it for printing temp, only heat it enough so the plastic begins to melt. Thirst then plastic melts it’s not really fluid ,more like slick.
So it would not drop from alone.
After bedleveling you could rise temperature to your print temp.

(Stephanie A) #5

Good idea. Depending on the material, 140C or so should be above glass transition enough to protect the nozzle. Really easy to test.

(Paul Gross) #6

I like to manually pre-heat the extruder to 170 (for PLA), then when that temperature is reached, pull off the softened ‘pig tail’ from the previous print, only then do I start the print under automatic control, which begins with the heat command, then g28, g29.

Even though the extruder gets hotter during the g28 and g29 subprograms, there was enough plastic removed from the bottom of the extruder tube that I never get any drips before the actual print.

But, I then needed to set slic3r to print a minimum of 2 skirt loops, because pulling off the softened ‘pig tail’ at 170 can sometimes take too much plastic from the bottom of the extruder tube.

(Amit Patel) #7

I know the lukzbot mini does something similar to this. Part of its start gcode is to heat up, retract some filament, lower temp, clean nozzel, level bed and then heatup to print temp extrude and print. It’s a long process but works very well as the tip of the nozzel is always clean. Also you could always add a purge option at the end of the gcode to get a primed tip